Flac - Sep 2005 - Re: Something's driving me crazy

I decode and then re-encode a FLAC file someone sent to me, and I get a
different file (about 3K
larger).

I have used:
 - the same version of FLAC.EXE (hash-checked) used to create the original FLAC
file
 - the same level of compression
 - no tag infos were included in the original FLAC file

I can't really figure out how could it be possible, but sometimes it happens
(of course many times I
get exactly the same 'binary' file).

Any idea?

Thank you very much for attention.

All the best.
Stefano

Stefano,

Perhaps "someone" used the --no-padding option, which saves quite a
bit of
space.  I use it all the time, even though it is not exactly recommended.

FLAC is guaranteed to give you back the original uncompressed audio data every  
time, but there is no guarantee that the compressed data will be the same (so  
long as it can be decoded).

Brian


Begin forwarded message:

I decode and then re-encode a FLAC file someone sent to me, and I get a  
different file (about 3K
larger).

I have used:
 - the same version of FLAC.EXE (hash-checked) used to create the original FLAC
file
 - the same level of compression
 - no tag infos were included in the original FLAC file

I can't really figure out how could it be possible, but sometimes it happens
(of course many times I get exactly the same 'binary' file).

Any idea?

Thank you very much for attention.

All the best.
Stefano

--- inishmor <inishmor@tiscali.it> wrote:
> I decode and then re-encode a FLAC file someone sent to me, and I get
> a different file (about 3K
> larger).
> 
> I have used:
>  - the same version of FLAC.EXE (hash-checked) used to create the
> original FLAC file
>  - the same level of compression
>  - no tag infos were included in the original FLAC file
> 
> I can't really figure out how could it be possible, but sometimes it
> happens (of course many times I
> get exactly the same 'binary' file).
> 
> Any idea?
> 
> Thank you very much for attention.
could be differences in padding, seektable, or other metadata,
or this:

http://lists.xiph.org/pipermail/flac/2005-July/000465.html

or this

http://flac.sourceforge.net/faq.html#tools__wave_flac_wave

Josh


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thank you Josh and Brian,

I have tried to change the padding and I succeded in getting a same size file 
... but still
different :-(
> ... different code paths through the encoder chosen at
> runtime that are optimized for different environments which can
> create different streams
That said, I have to give up, there will be still cases in which I cannot get
exactly the same FLAC
file.

Nothing dramatic. I was just curious about it.

Thank you very much for yours explanations.

Cheers.
Stefano

> --- inishmor <inishmor@tiscali.it> wrote:
>
> > I decode and then re-encode a FLAC file someone sent to me, and I get
> > a different file (about 3K
> > larger).
> >
> > I have used:
> >  - the same version of FLAC.EXE (hash-checked) used to create the
> > original FLAC file
> >  - the same level of compression
> >  - no tag infos were included in the original FLAC file
> >
> > I can't really figure out how could it be possible, but sometimes
it
> > happens (of course many times I
> > get exactly the same 'binary' file).
> >
> > Any idea?
> >
> > Thank you very much for attention.
>
> could be differences in padding, seektable, or other metadata,
> or this:
>
> http://lists.xiph.org/pipermail/flac/2005-July/000465.html
>
> or this
>
> http://flac.sourceforge.net/faq.html#tools__wave_flac_wave
>
> Josh
>
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>